Several types of compounds have been found to be useful in modifying or controlling the growth of plants. 2-Substituted pyrazoloisoindolones taught in U.S. Pat. Nos. 3,407,206 and 3,409,425 exhibit this property. Similarly, British 1,022,655 teaches the use of phenoxyacyl pyrazoles as plant growth regulants. Neither of these references suggest the novel pyrazoles of this invention.